There, you should see the option to associate a file type or protocol with a specific program. Click on that option, and allow the page to load. There, you should see a list of file extensions.

BearPup sometimes wants to open a file in one program, and other times open it in another. He asked the Answer Line forum for an easy way to do this.

Back in the pre-Mac OS X and macOS days, Apple’s System 9 and earlier relied on hidden metadata to associate files with apps. File extensions, those bits of text that follow a period at the end ...

File extensions have been a part of Windows since the beginning. They’re convenient and at the time the best solution to the problem of how to open a particular file.